Glow discharge tube



April Z8, 1936. D. cANADY 2,038,825

GLOW DISCHARGE TUBE Filed April 18, 1955 [llaga l wil/lill: 1

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Patented Apr. 28, 1936 UNITED STATES PATENT oFFlcE 2 Claims.

An object of my invention is the provision of improvements in a glow discharge tube, particularly in regard to an arrangement of a cathode and an anode together with an adjacent nontranslucent specularly reflecting mirror or reflecting surface or means which will eifect a distribution of the glow to an end of the tube highly intensified.

My present invention relates to means'for controlling and regulating the luminous intensity of a glowable gas or gases in a sealed envelope, by diverse electric instrumentalities and a reflecting means in association therewith in such a way and manner as to cause the glow rendered highly intensified to impinge on the end of the envelope.

Now it is well known in the art at present using glow lamps for producing a variable density sound tract on film that Iup to the present time the advantage of the glow lamp recording system has beenr retarded in practical usage by a number of shortcomings in the glow lamps themselves such as follows y (1) Low light intensity requiring that the lamp used be placed as close as possible to a mechanical slit or its equivalent, and hence in close proximity to the yfilm.

v (2) Lack of light uniformity the result of which required that each lamp be adjusted before it could be used withthe film strip.

(3) Erraticelectrical characteristics during the life of the glow tube thereby requiring constant watching and readjustment.

(4) Very short and indefinite life caused by the -blackening of the bulb or by change in the gas pressure or by the gas in and/or on the surfaces of theelectrodes themselves.

(5) A too large wattage consumption in the lamp thereby causing excessive heating of the lamp and elements with its consequent blackening and obstruction of light.

(6) Low sensitivity thereby requiring cooperatively large output from the recording amplifier used in connection therewith.

Therefore with my improved glow tube it is possible to overcome the aforementioned listed defects. And since the primary object of a glow lamp is to radiate actinic light, the glow tube must be so designed and constructed that the glowing gas within the bulb is greatly concentrated and localized as closely as possible to the end of the envelope through which the light is to pass.

And therefore it is an object of the invention to so design a glow tube such that the glowing gas within the bulb or envelope will be intensified through means immersed therein and concentrated at the end of the'envelope before it passes through the envelope to afllm. A

lIt is also an object of the invention.- to so arrange the electrodes and their associated apparatus so that increased light intensity may be ac- 5 complished with a smaller voltage than that used at present in the present type of glow tube.

It is also an object of the invention to produce a glow tube, the voltage current curve of which is a straight line, that is, that as the current in 10 milliamperes increases in multiples of 2 from2 to 4 to 6 to 8 to 10 to 12 to 14 etc. the voltage required increases in direct relation thereto, thus assuming that the voltage at 6 milliamperes to be 400, then at 12 milliamperes the voltageis 450, 15 and at 18 milliamperes the voltage is 500, thus giving a straight lline curve which `is at present rather unusual with the present gas filled devices.

The fact that the voltage-current curve is a` straight linel indicates that the glow tube main- 20 tains a constant impedance during all the signal "surges of the glow tube.

It is also an object of the invention to produce a new glow tube such that the heat dissipation within the tube is very small and this is accomplished by keeping the voltage and milliamperes down to a minimum while at the same time securing from the tube maximum intensity.

It is also an object of the invention to construct a glow tube such that under different frequencies 30. the characteristic curve of the glow tube is a straight line for all practical purposes. Y

Since much loss results from the present type` of glow tubes due to the'problem of spherical and chromatic aberration and coma, then it is an object of this invention to construct a workable unit giving greater brilliancy with small current, a lower temperature, a longer life to the tube, and a longer life to the batteries when such are used to operate the glow tube. 40

The reflected rays are, however, capable of being controlled by modifying the configuration of the reflecting means, for instance making the reflecting means of curvilinear configuration in which the radial plane of symmetry is perpendicular to the cathode and anode as distinguished from a plane reilecting surface. Y

It' is well known in elementary optics that reection occurs from any polished surface (mirrors) or the likeplaney concave, or convex or otherwise. 'I'he ray striking the mirror is called the incident ray, that returning from the reflected ray. I make use of this well known fact in my yimproved. glow tube or lamp to increase the luminous intensity of the glow of the inert noble gas surface, the position and form of the cathode and anodethereto as well as the material thereon to meet the particular size and shape, the proportions and dimensions of the electro-optical sys` tems where the glow tube may be used, for example with linear photographic sound records on nlm strips and such like.

' Further objects of the invention will appear' more f ully hereinafter.

The invention Yconsists substantially in the combination, location and relative arrangement ofthe parts, together with the novel methods employed in` accordance therewith, all as will be more fully hereinafter set forth, as shown in the accompanying drawing and pointed out with greaterparticularity in the appended claims.

Referring to the drawing:- f

Fig. 1 is a longitudinal sectional view illustrating andv embodying the principles of my invention.' Y

Fig. 2 is a fragmentary view illustrating a modication of the glow tube showing the electrodes mounted parallel to each other, and a mirror in proximity thereto.

Fig. 3 is a fragmentary view illustrating another modification of the glow tube showing the same provided with a plane mirror.

Fig. 4 is another modification of the glow tube showing the mirror integral with the pedestal and the pedestal integral withl the pinch or press. The base is not shown on the tube.`

Fig. 5 is a fragmentary view illustrating another form of the glow tube showing' a plurality of cathodes and anodes, and' provided with a plane mirror associated therewith.

Fig. 6 is another modification of the glow tube in longitudinal section the same being provided with a plane mirror.

.The same part is designated by the same reference character wherever it occurs throughout the several views. y

In accordance with my invention, I employ a transparent receptacle orv enclosing glass envelope I0 of suitable shape containing a noble glowable gas such as helium, argon or neon reputedv to be inert or a mixture of one of the said gases with a small quantity of hydrogen, nitrogen or oxygen. 'I'he tube containing a gaseous filling which consists of one or more of the rare and the active gases will during operation render aglowable or 4luminous cloud or discharge rich in ultra-violet rays which can emerge from the en- The leading-in wires 23 and 24 are positioned substantially coaxially of the tubes to the restricted necks wherein they are sealed in the glass or quartz forming the same. At the terminal or end of the wires 23 and 24 there is 5 provided discs of mica, asbestos paper, magnesia or other suitable material 25 and 23 to form an insulating wall between thegglass or quartz that shields the metallic electrodes. The cathode may be made of metal having a high melting point for instance tungsten or iron. The disc of asbestos paper or other suitable insulating substance used to form the insulating wall is folded or turned over the perimeter of the electrode and is sealed in the glass or quartz constituting the column or support in `which the electrode is'placed.

This construction provides a shielding means and prevents the creeping of the glow and tends to confine the electric discharge'to the exposed area of the cathode formed of suitable conduc tive substance, preferably metal.

Arising from the pinch or press and insulatingly supporting the same, there is provided a mirror or reflecting surface 21. The wires 23 and 23 that form the frame or support `for the reflecting means are sealed in the pinch or press. However the reflecting means may be supported by the columns supporting the electrodes or by the envelope itself by means of wires sealed in the columns or extensions in the` envelope, or the pinch may be made suitable to carry and support the mirror in desired position to the cathode and anode so that the impressed current will impin'ge thereon to increase the luminous intensity of the` gas cloud in the glow tube. The gas vcloud may 35 have a spectral selectivity with-in the ultra-violet region of the spectrum.

The end of the envelope 33 may be made thinner than the remainder of the tube asshown at 3I. 32, 33, 34 and 35, so that it will be of greater light- 40 permeability and less absorptive of the light rays passing therethrough. The end of theglow tube may be incurved as shown at 38. The luminous cloud focused upon the end of the tube thusformed will emerge in a streak of light. y

A mirror 31 having the desired form upon which is deposited a hard, brilliant, uniform illm of silver, the silver .deposit may be on the front or ythe back side of the mirror, and the mirror is placed f behind the electrodes to focus the luminous cloud 50 upon the end of the envelope in a well known manner.

In Fig. 2 the cathode 33 and the anode 40 are mounted parallel to each other, and the end of the glow tube is made thinner than the remainder 55 of the tube so that the absorption of lightvwill be less in passing through the transparent body forming the tube.

In Fig. 3 the cathode I3 and the anode I3 are similar to that shown in Fig. 1, but the mirror'4l is a plane surface, and the end of the glow tube is tenuous so that the absorption of light will be less in passing therethrough.

In Fig. 4 the pedestal-42 is integral with the 65 press or pinch 43, and the mirror 44 is integral with the pedestal. The cathode 45 is plateshaped, and the anode 43 is supported on a rod or wire 41. The anode is provided with a hole or aperture 43. 70

In Fig. 5 the cathodes yand the anodesare ar ranged in an alternative manner as at 43, 43 and '50, 50. The mirroris shown at-BI. In Fig. 6 the anode 52 is a rod, surroundedby a cathode of cylindrical helix conguration I3. 76

A plane mirror is shown at 54, obviously it may be of any suitable form.

;The mirror may be non-translucent thickly coated on its back with a coating not transparent to transmitted light and provided with a protective coating. The mirror may have a matte band peripherally or otherwise to conne the reection to a definite area.

It is well known that metal particles disintegrate from the cathode. These particles may fly against the mirror and matte the surface thereof as well as adhere thereto and form a bridge leading from the cathode to the mirror, this is prevented by the gap between the cathode and the mirror, and the shielding of the cathode by an annular ring of glass that extends upward from the surface of the cathode.

The tube thus constructed is exhausted by well known methods and lled with neon, argon or helium or a mixture thereof at proper pressure. If it is desired that the glow discharge should contain other rays, metal vapors capable of generating the rays may be added to the gaseous filling.

It is obvious that my invention is capable of being embodied in many different glow tube arrangements and should not be construed as limited to those herein illustrated and described, but only by the scope of the appended claims.

Many other modications and changes in details will occur to those skilled in the art without departing from the spirit and scope of my invention as dened in the claims, but having now set forth the objects and nature of my invention, and having shown and described structures embodying the principles thereof and illustrated the method employed in accordance therewith, what I claim as new and useful, and of my own invention, and desire to secure by Letters Patent, iss- 1. A glow discharge tube containing a noble glowable gas, a. rearwardly inclined cathode and anode for producing a glow discharge in the gas, a mirror of segmental cylindrical conguration rearwardly of and in proximity to said cathode and anode and supported between the cathode, anode and a press in the tube, the tube having a light-transmitting end portion of cylindrical segmental configuration forward of the cathode and anode, the said portion being utilized to maintain the initiated glow-discharge highly intensified in a light streak.

2. A glow discharge tube containing inert noble glowable gases, a rearwardly inclined cathode, a rearwardly inclined anode, a mirror positioned rearwardly of the cathode and anode and in proximity thereto, and xed between the cathode, the anode and a press in the tube.

DON CANADY. 

